REPORT | WU16 1-3 Portugal
The home team dominated for large spells and took the lead on 11 minutes when Beatriz Pedras applied the finish after good work by Carolina Santiago to keep the play alive.
A goal from Ballingarry AFC ace Katie Lawlee threatened to spoil the day for the hosts but then Reto netted twice - once from the penalty spot - to seal the win.
After scoring early on, Portugal kept the pressure on with Irish goalkeeper Katie Keane kept busy and the home team hitting the woodwork too.
Ireland's best chance to score in the first half came on the half hour mark when DLR Waves attacker Joy Ralph raced onto a long pass but her shot was diverted away by goalkeeper Carolina Alves.
On 64 minutes, Ireland got the goal that their positive play merited. A cross from Lia O'Leary was hooked into the air by Luana Rafael and Lawlee reacted quickest to force the ball over the line inside a crowded six-yard box.
It didn't take long for Portugal to hit back. On 67 minutes, substitute Reto blasted in a penalty after defender Aoife Turner was adjudged to have handled inside her own area.
The hosts continued to break forward at pace and shoot on sight with Luana Barata seeing a shot strike the post and Reto's effort on the rebound hitting the crossbar.
The victory was wrapped up on 80 minutes when Reto broke the offside trap, raced through, rounded the goalkeeper and fired into an empty net.
The teams will meet again on Wednesday afternoon.
Republic of Ireland: Katie Keane; Skye Corcoran (Aoife Turner 46), Anna Cantwell, Heidi Macken (Jill Giles 83), Alice Lille; Elle Dolan (Jessica Fitzgerald 62), Aoife Kelly (Orlaith Doherty 78); Katie Lawlee (Amy Madden 78), Jodie Loughrey, Lia O'Leary (Jodie Griffin 83); Joy Ralph (Grace Flanagan 46).
Portugal: Carolina Alves; Erica Cancelinha, Luana Rafael (Inés Meninas 85), Maria Chaves (Matilde Nave 62), Ana Filipa Riberio (Carolina Pimenta 85); Rita Almedia (Rita Melo 81), Luana Barata, Beatriz Pedras (Alice Reto 62), Maria Luiza Gaspar (Neide Guedes 62), Nicola Cassama; Carolina Santiago (Daniella Serrao 62).
Referee: Silvia Santos (Portugal).